With conventional doorlock assemblies, the doorknob is typically threaded onto a square operating shaft and the shank of the doorknob provided with a tapped hole into which a set screw is threaded. The set screw is adapted to be threaded into the tapped hole and set against either of the four flat side surfaces of the operating shaft to lock the doorknob against rotation on the shaft. In certain situations, the four positions at which the doorknob can be secured to the operating shaft are insufficient. For example, it may be that the setting of the set screw against one flat face of the operating shaft will position the doorknob too tightly against the door while backing the doorknob off to move the set screw to the next flat surface will provide a loose attachment. In such a situation the loose attachment must be used in order to permit the doorlock mechanism to open and close properly. In this position of the doorknob, the user simply accepts the fact that the loose connection of the doorknob is unavoidable if proper mechanical functioning of the lock is desired.
In another situation, the four position setting of conventional doorknobs has also been found to present actual operating problems. In particular, where the doorknob is other than circular in shape, it sometimes occurs that the most proper setting of the doorknob, as far as tightness of the door is concerned, positions the knob so that turning during opening and closing of the door is interfered with by the door jamb. For example, where the doorknob is in the shape of a handle extending laterally of the operating shaft, this type of interference is most likely to occur. In order to avoid it with the presently available doorlock assemblies, the handle must be set at a position where it extends away from the door jamb as much as possible. Obviously, this position may not be the best as far as tightness of the doorknob against the door; and it may be necessary to back the doorknob off more than one-quarter turn to prevent the interference with the door jamb. It will be evident that this may further add to the looseness with which the doorknob must be positioned in order to at least obtain proper opening and closing of the doorlock mechanism.
In addition to the above operating deficiencies of the conventional type of doorlock assembly, the limited positions in which the doorknob can be locked to the operating shaft may simply be aesthetically unpleasing. For example, the doorknob may have a configured pattern which should be rotated to a particular orientation for providing the most aesthetic appearance. With the square shaft and the four possible settings of the doorknob of conventional constructions, the particular desired positioning of the doorknob may not be readily possible.